In 1967, during the Vietnam War, the United States Naval aircraft carrier U.S.S. Forrestal experienced a catastrophic accident. Specifically, a “Zuni” rocket was accidentally fired from an aircraft about to be launched from the carrier, which resulted in ignition of a fuel fire that nearly destroyed the carrier. It was later discovered that the Zuni rocket's motor had, without command of pilot or crew, ignited. The ignition of the electrically triggered rocket motor was then determined to be a result of electromagnetic interference and consequential triggering effect from the carrier's radar.
Other instances of accidental triggering have been experienced in mining and civil engineering projects, where radio frequency interference has caused uncommanded detonation of blasting caps and other explosives used at such locations.
Since the Forrestal accident, all ordnance that employs electric triggering devices is designed and tested under rules which govern electronic packaging and shielding for minimizing electromagnetic effects thereon. In mining projects and the like, a protocol of prohibiting radio transmissions anywhere in proximity to the site has been strictly enforced.
Electrically triggered explosives are well known, and have unfortunately been successfully utilized by individual terrorists, terror organizations, and other criminals without warning for destruction of military and civilian targets alike.
These criminals have frequently utilized crudely made or so-called “improvised” explosive devices to carry out their despicable acts. These improvised explosive devices are commonly constructed from commercially available components and are assembled with little technical expertise. Such improvised devices are typically simple in their construction, comprising a package or housing containing explosives, an electronic detonator to ignite the explosives, a timer or manually operated switch to trigger the detonator, and a battery to power the electronic components. Improvised devices are, due to their simplicity, easily concealed and therefore there has been virtually no defense against them.
Therefore, it would be desirable to utilize what was tragically learned from accidents like that of the Forrestal, to combat the use of improvised explosive devices.